1. Field of Invention
The present invention relates to an image data compression/expansion system which is capable of compressing and expanding image information at a very high speed, with the provision of an image data expansion device of a purely hardware-oriented structure.
2. Description of the Related Art
There have conventionally been proposed various kinds of image data compression/expansion techniques. In general, a data compression of this kind is achieved by subjecting digitized image data to an arithmetic processing based on a predetermined algorithm such as a prediction coding (for example, ADPCM) and a transform coding (for example, DCT). The thus compressed image data can then be expanded by decoding such that it is subjected to an arithmetic processing based on an algorithm which is an inverse of that for the compression. These compression processing and expansion processing are usually carried out with a high-speed digital signal processor.
However, since the above-described conventional image data compression/expansion techniques are based on the arithmetic processing of digital image data, there is a certain limit in processing speed even when a high-speed processor of exclusive use for arithmetic operation is used. In addition, such a high-speed processor is generally very expensive, so that the cost of the system as a whole will become also very high.